Organic electroluminescent device and display apparatus

Abstract

An organic electroluminescent device for emitting red light is disclosed. The device includes: an anode; a cathode; and an organic layer including a light-emitting layer, wherein the light-emitting layer contains a red light-emitting guest material and a host material composed of a polycyclic aromatic hydrocarbon compound having a skeleton with 4 to 7 membered rings, and a photosensitizing layer containing a light-emitting guest material generating green light is provided adjacent to the light-emitting layer.

1 . An organic electroluminescent device for emitting red light comprising:
 an anode;   a cathode; and   an organic layer including a light-emitting layer provided between the anode and the cathode, wherein   the light-emitting layer contains a red light-emitting guest material and a host material composed of a polycyclic aromatic hydrocarbon compound having a skeleton with a 4 to 7 membered ring, and   a photosensitizing layer containing a light-emitting guest material generating green light is provided adjacent to the light-emitting layer.   
   
   
       2 . The organic electroluminescent device according to  claim 1 , wherein
 the skeleton of the polycyclic aromatic hydrocarbon compound is selected among pyrene, benzopyrene, chrysene, naphthacene, benzonaphthacene, dibenzonaphthacene, perylene and coronene.   
   
   
       3 . The organic electroluminescent device according to  claim 1 , wherein
 a compound represented by the following general formula (1) is used as the host material of the light-emitting layer:   
     
       
         
         
             
             
         
       
     
     wherein R 1  to R 8  each independently represents hydrogen, a halogen, a hydroxyl group, a substituted or unsubstituted carbonyl group having not more than 20 carbon atoms, a substituted or unsubstituted carbonyl ester group having not more than 20 carbon atoms, a substituted or unsubstituted alkyl group having not more than 20 carbon atoms, a substituted or unsubstituted alkenyl group having not more than 20 carbon atoms, a substituted or unsubstituted alkoxyl group having not more than 20 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted silyl group having not more than 30 carbon atoms, a substituted or unsubstituted aryl group having not more than 30 carbon atoms, a substituted or unsubstituted heterocyclic group having not more than 30 carbon atoms or a substituted or unsubstituted amino group having not more than 30 carbon atoms. 
   
   
       4 . The organic electroluminescent device according to  claim 1 , wherein
 the photosensitizing layer is provided adjacent to the light-emitting layer and between the light-emitting layer and the cathode.   
   
   
       5 . The organic electroluminescent device according to  claim 1 , wherein
 red light generated in the light-emitting layer is multiply resonated in any layer between the anode and the cathode and extracted from any one side of the anode or the cathode.   
   
   
       6 . The organic electroluminescent device according to  claim 1 , wherein
 a perylene derivative, a diketopyrrolopyrrole derivative, a pyromethene derivative, a pyran derivative or a styryl derivative is used as the red light-emitting guest material.   
   
   
       7 . The organic electroluminescent device according to  claim 1 , wherein
 a hole transport layer provided adjacent to the light-emitting layer includes a plurality of layers each of which has different materials from each other, and the layer adjacent to the light-emitting layer includes an organic material represented by the following general formula (2):   
     
       
         
         
             
             
         
       
     
     wherein A 1  to A 3  each independently represents an aryl group or a heterocyclic group. 
   
   
       8 . The organic electroluminescent device according to  claim 1 , wherein
 a hole transport layer provided adjacent to the light-emitting layer includes a plurality of layers each of which has different materials from each other, and the layer adjacent to the light-emitting layer is configured by using an organic material represented by the following general formula (3):   
     
       
         
         
             
             
         
       
     
     wherein
 A 1  to A 4 , Z 1  and Z 2  each independently represents hydrogen, a halogen, a hydroxyl group, a carbonyl group, a carbonyl ester group, an alkyl group, an alkenyl group, an alkoxyl group, a cyano group, a nitro group or an amino group, 
 A 1  to A 4  may constitute acyclic structure in a site adjacent to each other, 
 Ar 1  and Ar 2  each independently represents an aryl group or a heterocyclic group, and 
 B 1  and B 2  each represents hydrogen, an alkyl group, an aryl group or a heterocyclic group. 
 
   
   
       9 . The organic electroluminescent device according to  claim 1 , wherein
 a hole transport layer provided adjacent to the light-emitting layer includes a plurality of layers each of which has different materials from each other, and the layer adjacent to the light-emitting layer is configured by using an organic material represented by the following general formula (4):   
     
       
         
         
             
             
         
       
     
     wherein
 Ar 1  and Ar 2  each independently represents an aryl group or a heterocyclic group, 
 R 1  to R 8  each independently represents hydrogen, a halogen, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, a hydroxyl group, an amide group, an aryl group or a heterocyclic group and may constitute a cyclic structure in a site adjacent to each other, and 
 X represents a divalent aromatic ring group. 
 
   
   
       10 . A display apparatus comprising a plural number of organic electroluminescent devices for emitting red light including an anode, a cathode, and an organic layer including a light-emitting layer, wherein
 the light-emitting layer contains a red light-emitting guest material and a host material composed of a polycyclic aromatic hydrocarbon compound having a skeleton with a 4 to 7 membered ring, and   a photosensitizing layer containing a light-emitting guest material generating green light is provided adjacent to the light-emitting layer.   
   
   
       11 . The display apparatus according to  claim 10 , wherein
 the organic electroluminescent device is provided as a red light-emitting device in a part of plural pixels.   
   
   
       12 . The display apparatus according to  claim 11 , wherein
 the photosensitizing layer of the organic electro-luminescent device covers a plurality of pixels so as to function as a common light-emitting layer.   
   
   
       13 . The display apparatus according to  claim 11 , wherein
 an organic electroluminescent device for blue light and an organic electroluminescent device for green light are provided together with the red light-emitting device on the substrate.